Abstract: - Besides, comparing the measured performance and the exhaust emissions (exhaust smoke and oxides of nitrogen), a detailed combustion analysis of the acquired cylinder pressure histories on these samples has been attempted. From this analysis, the maximum reduction in exhaust smoke level is found to be 32 % and the CO level are decreased by 25 % with the 20% Pongamia methyl ester as compared to that of the diesel. In the first stage of the work, the effects of various nozzle opening pressures like 180 bar, 200 bar and 200 bar with 20% Pongamia methyl ester blend are investigated. It is observed that the nozzle opening pressure at 200 bar showed an improvement in brake thermal efficiency and 42% reduction exhaust smoke level with 10% increase in NOx concentration at full load compared to that of the base engine with diesel fuel. The peak pressure and heat release are increased by 3 bar and 4 J/ oCA respectively at full load. Ignition delay and the combustion duration are also decreased due to better atomization and vaporization air and fuel at higher injection pressures.. In the second stage of the work, the effect of Titanium oxide coated (500 microns Ceramic coating by plasma spraying method) piston with 20% Pongamia methyl ester blend is investigated. It is observed that 20% PME showed an improvement in the engine brake thermal efficiency by about 1.6% and 34% reduction in exhaust smoke level and the CO and HC emissions are also decreased compared to that of the base engine with diesel fuel. The peak pressure and heat release are increased by 4 bar and 8 J/ oCA respectively at full load. vii | P a g e In the third stage of the work, the effect of Di-ethyl ester as fuel additive with 20% Pongamia methyl ester blend is investigated. It is observed that the DEE with 20% PME showed an improvement in the engine brake thermal efficiency and 17% reduction in exhaust smoke level and the CO and HC emissions are also decreased compared to that of the base engine with diesel fuel. The peak pressure and heat release are increased by 2.5 bar and 6 J/ oCA respectively at full load. Ignition delay and the combustion duration are also decreased due to better combustion of the oxygenated fuel and more oxygen present in the biodiesel. Finally, it is concluded that the 20 % Pongamia methyl ester blend with TiO2 coated piston engine operation gave a better performance and considerable reduction in exhaust emissions and also the combustion properties are improved. This may be due to more heat retainment in the ceramic coated piston compared to that of the other two techniques. The NO emissions for 10% DEE with B20 blend are almost equal to that diesel fuel with the base engine.